550 liEPORT OF COMMISSIONER oF FISH .\.\1) FISIIEKIEl^. 



Ill sections made in the vicinity of the reproductive aperture, back of 

 tlic posterior fourth of the hody, the cuticle Avas found to consist of two 

 Uiyers (Fij;". 20, e, c). Tlie outer or eijidcrinal hiyer appears to be 

 sloughiiiji' off from the inner, uniform cuticular hiyer. Within the 

 cuticle is a very thin layer of fine longitudinal fibers. Tliis is suc- 

 ceeded by a thick granulo-fibrous layer, which contains numerous 

 granules and nuclear bodies, Avhich latter stain deeply in carmine. 

 There are also, especially in the older speciuiens, small clusters of lon- 

 gitudinal muscular fibers in this layer (Fig. IG, /). The inner portion 

 of this layer is somewhat open or areolar. The water vascular system 

 consists of an indefinite numb<'r of vessels not clearly defined and of 

 various sizes, which, in the posterior ])art of the body, in the vicinity 

 of the reproductive aperture, lie in the inner i)ortion of the subcuta- 

 neous granulo-fibrous layer (Fig. IG, w). This characteristic branching 

 of the water- vascular system appears to be identical with that observed 

 by G. R. Wagener (Natuurk. Verb. Haarlem, xiii, OG; Tab. vii, 2). 

 Next within the granulo-fibrous layer is a layer of longitudinal mus- 

 cular fibers (Figs. IG, 17, 18, 20, Im). This does not constitute an 

 unbroken layer, but consists of numerous clusters of longitudinal fibers 

 which lie in the midst of the connective tissue and surround the cen- 

 tral space. The latter contains the genital organs. A terminal pore 

 leading into a short duct with thick walls Avas observed in transverse 

 sections through the posterior end of a small specimen. The duct 

 enters posteriorly from near one margin and not from the extreme tip, 

 and continues anteriorly to the posterior vitelline gland. The same 

 was observed in transverse sections of larger specimens, where it 

 appeared first in the posterior sections as a pore entering one of the 

 margins, and was soon seen, in succeeding anterior sections, toward 

 tlie middle of the sections as an elongated opening with strong walls of 

 connective tissue of irregular thickness. In the smaller specimens 

 strong connective fibers run from the anterior end of this cul-de-sac. 

 This organ is doubtless the terminal pulsating organ common to larval 

 cestods. 



Genital orffcins. — The testes begin a short distance back of the head. 

 In a young specimen they began about the anterior third; in an older 

 specimen they began almost immediately behind the head. They con- 

 sist of globular masses (testicules) of granular protoplasm in the 

 younger specimens. In the older specimens they are irregular in 

 shape ami relatively smalier. The granules are collected into minute 

 glolmlar clusters and appear in the sections as circular or oval nests of 

 nuclei. The testes extend posteriorly nearly to the reproductive aper- 

 ture, which is about the posterior fourth or fifth of the body. 



In front of the genital aperture there is a voluminous tube which, 

 after making numerous convolutions, coitimunicates with the cirrus bulb. 

 This tub© is evidently the vas deferens {vide Figs. 13, 14, 15, 16). In 

 sections of a large specimen it was seen to contain numerous masses 



